When it comes to flying, Southwest makes the experience a lot easier to handle than its peers.

That's according to a new index to be released today that ranks companies based on how simple they are to engage with.

Southwest was the highest-ranked travel company, coming in at No. 9 out of 125 businesses whose brands are well-known in the U.S., according to a survey by New York-based strategic branding firm Siegel +Gale. The low-cost carrier leaped six spots from where U.S.-based respondents ranked it last year. Amazon was No. 1.

The perception that Southwest offers fair prices that don't dramatically spike because of a host of extra fees being tacked on is key to customers feeling the airline is easy to deal with, says Brian Rafferty, director of global research for Siegel + Gale. "Transparency is one thing Southwest is doing well,'' he says, "and people also . . .feel they have very good service and they care about the customer.''

Siegel +Gale's annual survey includes a global simplicity index, as well as separate rankings for six regions including the U.S., the Middle East and the United Kingdom. Taken between May 3 and July 2, there were roughly 1,500 respondents in the U.S. consumer survey.

JetBlue came in at No. 44, jumping 24 spots from last year. But the rankings of the low-cost carriers stood in stark contrast to those of their larger peers, who hovered near the bottom of the U.S. rankings. US Airways came in at 103, American was ranked 105, United was 115 and Delta was 116.

The airlines are "one of the industries where there's the biggest gap between the leaders and the laggards,'' Rafferty says.

The network carriers get negative reviews for piling on extra fees and not being more up front about them, said Kathleen Kindle, a Siegel +Gale strategy director for brand development. "People are super price-conscious and they don't want to know there's an extra $150 tacked on if they change their flight,'' she said.

Rahsaan Johnson, a spokesman for United, said, "We've heard our customers' concerns loud and clear. We're updating our online capabilities, our mobile apps and the tools and training we give our employees to deliver better service and solve customers' problems more quickly than we could in the past.''

Victoria Day, spokeswoman for the airlines trade group Airlines for America, said, "U.S. airlines understand how important it is to be clear and transparent in communicating with customers so they are fully informed from booking a reservation through to flight completion, and airlines continue to enhance their communications channels, including social media sites like Twitter and Facebook to better engage with customers.''

Some consumers in the Siegel +Gale survey also voiced concerns about the car rental industry. While Enterprise jumped 38 spots from last year to 57, Alamo came in at 84, Hertz was 97 and Budget was 98. Rafferty and Kindle said that consumers were turned off by complicated rental contracts and fees for insurance, gas and other extras.

Siegel +Gale, which helps companies simplify their brand experience, believes that simplicity can boost business. Among U.S. consumers, 75.5% of survey respondents said they'd be more likely to recommend a brand or company if it provides a more streamlined experience than its peers or competitors.

"You think about our lives today and all the experiences people are having with multiple screens and multiple interactions,'' Kindle says. "Brands that offer a respite from all of that, a transparent and easy experience to their customers'' can have an advantage. "We could all use a little less complexity in our daily lives.''